..06). The findings suggest that a connection may exist between sexual orientation and genes both on chromosome 9 (where blood type is determined) and on chromosome 1 (where the Rh factor is regulated)...

Social status and the secondary sex ratio: new evidence on a lingering controversy

Lee EllisMinot State University, USASoc Biol 49:35-43. 2002

..No evidence was found to support the hypothesis that parental social status has any significant effect on the sex ratio of offspring...